Quote Originally Posted by TXSurf4 View Post
The 450 is actually the 460 with a smaller diameter exhaust. I believe it actually has different hard parts than the 400 like different heads.


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The only real hard part that would differ is possibly cams and for a engine that you want peak tq at 3500 rpm, I doubt they changed the cams.

Most of the power gains would be from tuning (timing and fuel mapping) to take advantage of higher octane fuel. Also by raising the max rpm (5300 vs 5000) they get some extra HP under the curve.

Going from 89 to 93 octane would easily allow 3-4 degrees advanced timing and that is about 10ft lbs per degree of advance.

I know the 450 will run on 91, but it loses some power as knock sensors would have to pull timing.

Also correct on skiers using a slightly restrictive exhaust and losing some power from the 460.


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